Adjustable high ohmic resistance and method of manufacturing same



Oct. 22, 1929. J. KREMENEZKY ADJUSTABLE HIGH OHMIC RESISTANCE AND METHOD OF MANUFACTURING SAME Filed July 11, 1928 My WWH I 7 Patented Oct. 22, 1929 UNITED STATES PATENT OFFICE 301mm: xnnmmrzn,

OI VIENNA, AUSTRIA Application flied July 11, 1928, Serial No.

applied to the carrier, that it is brought into electric connection with the contact elements or tapping points. As a resistance body preferably a flexible core having closel wound thereon a thin resistance wire is use The resistance body is then wound on the carrier. In the present resistance the delicate resistance body does not come into mechanical contact with the contact yoke which on the contrary slides on the special contact elements. The arrangement and method of manufacture of the contact elements according to the invention permits a simple and cheap manufacture and the obtention of a large number of resistance values. Furthermore by means of a resistance according to the invent-ion very high resistances may be included in a small space; The main field of application of the resistance according to the invention is the radio branch in which it is for instance adapted to replace the so called sillite resistance. The subject matter of the invention and its constituent parts are, however, adapted for manifold other applications.

The drawing showsby way of example a I constructional form of .the resistance according ,to the invention, Figures 1 and 2 illustrating two diflerent stages of manufacture. Fig. 3 is a section on the line 3, 3 Fig. 2 and Fig. 4 shows a resistance readily mounted for use.

As the main body serves the bar shaped carrier 1 of an insulatin material of sufficient mechanical strengt such as vulcanized fibre or wood. The proportions of the dimensions of this carrier and therefore of the entire resistance depend entirely on the purpose for which it has to be used. The carrier is provided with two series of teeth 2 and 3 opposite each other. On the teeth 4 small recesses 5 are arranged. Now at first a thicker wire 6, for instance of nickel, which may be called the contact wire, is so wound around the carrier, that it alternately comes onto the tooth 4 and into the recess 5 291,766, and in Austria March 81, 1928.

provided thereon and into a space 7 between two successive teeth of the two series of teeth. The two ends 11 of the wire are repeatedly passed through holes 8 in the carrier and thus secured in position.

On one side of the carrier the middle parts 9 of the half windings of the contact wire located on this side are cut away and strips 10 of an insulating material such as paper are placed on both sides of the carrier. The width of the strips is such, that they extend to about the bottoms of the spaces 7 between successive teeth.

After this intermediate product has been made, the resistance body proper 12 is wound around the carrier. It consists of a flexible core, for instance a number of silk threads around which the thin resistance wire for instance a tungsten wire is wound. The resistance body is then placed into the spaces 7 of the carrier as is shown in Fig. 3. Its ends are secured for instance b clamping, between the carrier 1 and the strips 10. Each winding of the resistance body is in electric connection with the part of the contact wire 6 in the corresponding space 7 approximately in one point only. But the corresponding piece of the contact wire also passes over a tooth 4 on the opposite side of the carrier, so that the current may pass at these points to a yoke 13 sliding over the teeth. The yoke 13 is'so constructed that it always makes contact with at least one contact element. At both ends of the carrier l a piece of the strip 10 is cut away as is indicated b the broken line 14 in Fig. 2. The ends 11 of t e contact wire are uncovered thereby and one of them as shown in Fig. 2, the right hand one, is clamped by washers and screws for connecting the resistance to the circuit. Holes 15 for passing therethrough the screws are provided in the carrier. .As long as the contact yoke 13 is at the right hand end f the carrier 1 (Fig.1) the resistance includgd in the circuit is zero. In theextreme left=hand position the connection is broken since the extreme left hand tooth or teeth 4 do not carry the contact wire.

According to Fig. 4 the resistance is wound around a circular disc 16'. The carrier 1 is secured to the disc by means of washers 17 and flexible insulating 1 screws 19 and 20. The right hand screw 20 is electrically connected to the end 11 of the contact wire 6, the left hand screw 19 is connected to the contact arm 18 carrying the yoke 13 and rotatably mounted in the disc 16. On the opposite side of the disc is located the actuating knob of the contact arm.

A resistance constructed according to Figs. 1 and 2 of a size of 15 by 1 centimeters may have a resistance value of 100,000 ohms'which may be regulated in steps of 2,000 ohms, but still higher resistance values may be readily obtained.

What I claim is:

1. An adjustable resistance comprising an insulating substantially rectangular resistance carrier having indentations on one of its long sides and projections on its opposite side, a contact wire helically wound around the said resistance carrier the said contact wire passing through the said indentations and sides of the said carrier placed over the said contact wire, a resistance body consisting of a core and a continuous resistance wire he cally wound around such core, the said resistance body wound around the said resistance carrier and the said insulating coverings entering into the indentations on one of its long sides and between the projections on its opposite side, whereby points of the resistance wire distant from each other are brought into permanent electric contact with the successive bights of the contact wire in the said indentations, means for permanently electrically connecting .one outer end of the said contact wire with a contact arm in permanent electric connection with the other terminal of the adjustable resistance and adapted to move along and make contact with successive bights of the said contact wire passing over and projecting beyond the said projectlons. 4.

2. An ad ustable resistance comprising a substantially rectangular resistance carrier of signature.

' i J OH. KREMENEZKY.

resistance material, a contact wire helically wound around the said resistance carrier, a part of each of the windin s of the contact wire located on one side 0 the said carrier being removed, insulating coverings on both sides of the said carrier extending over the said contact wire, a resistance body consisting of a flexible insulatin core, and a continuous resistance wire helica y wound around such core, the said resistance body Wound around the said resistance carrier and the said insulating coverings, whereby ance wire distant from eac other are brought into permanent electric contact with the successiv'e bights of the contact wire, means for permanently electrically connectingone outer ints of the resist- 

